Electric system of lift control



July 14, 1936. N. c. SMART ELECTRIC SYSTEM OF LIFT CONTROL Filed March50, 1935 4 Sheets-Sheet l urs dr3 drz m 'IwvmTo/ 7 C.

July 14, 1936. N. c. gMART 2,047,805

ELECTRIC SYSTEM OF LIFT CONTROL FilecLMarch 50. 1935 4 Sheets-Sheet 2 afirog 5y. 7

July 14, 1936. N. c. SMART ELECTRIC SYSTEM OF LIFT CONTROL' Filed March50, 1935 4 Sheets-Sheet 4 Y. E w 0 B+m 2 Y M ma YA? b4 Yc +U MM 6: W

I/l/VE/l/TOR Patented July 14, 1936 UNITED STATES PATENT OFFICE NormanCarol Smart,

Binley, near Goventry,

England, assignor to The General Electric Company Limited, London,England Application March 30, 1935, Serial No. 13,810 In Great BritainMarch 26, 1934 10 Claims.

This invention relates to electrically controlled lifts and like limitedtravel mechanisms, and more especially to lifts of the variety operatedby the user.

Lifts are known in which the operation of a push button at a particularfloor by a user brings the lift to that floor, whereupon the user entersthe lift and by depressing one of a number of buttons in the lift causesit to travel to the required floor. This type of system, thoughmoderately simple, is not the simplest possible, in that the user mustperform two separate operations, firstly, that of calling the lift tothe floor where it is required, and secondly, that of giving anindication as to its destination when it has arrived there.

Lift controlling systems are also known in which a user, by theperformance of a single operation, affects the controlling mechanism ofthe lift so as to bring the lift to or to stop it at the required floorand thereafter to cause it to travel to and stop at a required floor. Toaccomplish this, at each floor is provided a series ofelectromagnetically locking push buttons bearing the numbers of theother floors served by the lift. A caller at one floor presses a buttoncorresponding to the floor to which he wishes to travel, whereupon thelift is brought to or stopped at the floor where the button has beendepressed, and, after the caller has entered the lift, is causedtotravel to the floor required and to stop there.

Systems of this nature possess certain disadvantages. One of these isthat locking pushbuttons have not been found suitable for use on liftsliable to heavy traffic. 'Another is that call storage at the variousfloors served by alift necessitates a larger number of wires being runin the lift shaft, and a third disadvantage resides in that if 72 floorsare served by the lift, the number of call storage devices, i. e.electromagnetically locking push-buttons or relays-has hitherto beensome multiple of 12 This, for a lift serving a large number of floors,renders the cost of such a scheme prohibitive.

According to the present invention, in a useroperated lift controllingsystem in which a single operation only is performed both to call thelift to the user and thereafter to direct it to the required floor,calls are registered on a group of electromagnetic storage devices, suchas relays, which are k n in number, where n is the number of floorsserved by the lift, and 7c is a constant. Calls to be attended to by thelift are divided '-into three classes, effective calls, storedcalls up,and stored calls down, each floor being provided with three relays, eachrelay representing one of the types of call defined. The depression of abutton at a floor operates one relay in each of two floor groups, therelays operated being determined not only by the position of the liftrelative to the floor on which the push is operated, but also by thedirection in which the lift is or was previously travelling, and by thedirection in which the caller wishes to travel. Thus the effective-callrelay is operated when the lift is travelling towards or has just beentravellingtowards the floor where the push-button isoperated, and in thedirection that the user requires to travel. The down-call storage relayis operated when the lift is travelling or has just travelled away fromthefloor where the pushbutton is operated, and the required direction oftravel of the lift is downwards, whilst the upcall storage relay isoperated under similar conditions to the above, except-that the requireddirection of travel is upwards. The lift travels in one direction untilall effectivecalls in that direction are answered, whereupon storedcalls for the opposite direction are transformed into effective calls,and the lift reverses and answers them.

A group of follower relays, additional to those used for storage, isprovided, the relays of which operate in synchron-ism with the positionof the lift in the shaft; its relays, in conjunction with the threerelays previously mentioned as being provided at each floor, control theoperation of two further relays which affect drive of the lift up ordown.

The usual facilitiesas regards maintaining the lift stationary whenany-one of the floor gates or doors is opened, and of arresting itsmotion by limit switches at the end of its travel, may be provided. Inaddition a delay device may be fitted such that when the lift stops at aparticular floor, it remains at this floor for a predetermined timealthough the lift doors are not opened. After this time has elapsed itbecomes once more free-to attend to other calls. If necessary, the liftmay, afterfurther delay, be caused to run to a predetermined parkingposition and there stopped, provided that no effective or stored callsare made before the lift reaches the parking position. If it remains outof use for a still further period, the motor-generator set or powersupply driving'the lift motor may automatically be shut down ordisconnected, though it is re-started or reconnected on the appearanceof a call.

In order that the invention may be clearly understood, one form of liftcontrol in accordance therewith will now be described by way of examplewith reference to the accompanying drawings.

The drawings show a circuit diagram of the lift control system adaptedto serve four floors, the circuit being divided into three parts, shownin Figures 1a., 1b, and 3, for convenience in representation, and Figure2 is an explanatory diagram for use in readily tracing the relays andtheir respective contacts in the other figures. The location of therelays and contacts are indicated by arrows in Figure 2; an arrowpointing to the left indicates that the relay or control is to be foundin line with the arrow, in Figure 1a or Figure lb, while an arrowpointing towards the right indicates that the relay .or contact is to befound in line with the arrow, in Figure 3.

As shown in Figure 1a, a lift carriage LC is suitable suspended from acable which passes over a hoisting drum directly coupled to and drivenby a lift driving motor M.

A spring actuated brake operated by an electromagnetic brake coil BS isprovided for preventing rotation of the hoisting drum when the hoistingmotor is not in operation. The brake coil BS when energized, releasesthe brake.

Energizing circuits for the field winding of the driving motor M arecompleted through contacts of an up-direction relay R and adown-direction relay K.

The up-direction relay R and the down-direction relay K are preventedfrom operating unless a starting relay ST is operated, so that the liftdoes not move until this relay ST is energized. The energizing circuitof the starting relay ST comprises the gate locks VG, on the groundfloor gate and VI, V2, and V3 on the first, second and third fioor gatesrespectively, an emergency stop push button VC in the lift carriage LCand limit contacts TL and BL respectively mounted near the top andbottom of the lift shaft and operated should the lift carriage by anymeansoverrun its normal extent of travel in the shaft.

The group of follower relays GF, IF, 2F, and SF is provided for thepurpose of following the movement of the lift in the shaft. Followerrelay GF is energized when the lift is at or near the ground floor,follower relay IF is energized when the lift is at or near the firstfioor and so Lift actuated position indicating contacts J I, J2, and J3are provided in the lift shaft midway between the ground floor and thefirst floor,

midway between the first and second floors, and midway between thesecond and third floors respectively. These contacts are actuated by camoperating means CJ on the lift carriage itself and serve to determinewhich of the follower relays GF, IF, 2F or 3F is to be energized. Theselift actuated contacts J I, J2, and J3 are operated towards the left inthe drawing by the passage of the lift carriage in an upward directionand to the right as the carriage moves downwards.

A stop relay P of the well-known inductor pattern is mounted on the liftcarriage and remains operated so long as the lift carriage is at or neara floor. The operation of a relay of the inductor pattern is well-knownand need not be fully described herein; it should be pointed out,however, that for clarity in representation one of the four necessaryinductor plates FF is shown at the stop relay P in Figure la of thedrawings.

If desired, this stop relay P may be of the mechanically actuated typeand not necessarily of the inductor pattern.

In the representation of the contacts in the diagram, it has beenassumed that the lift carriage LC is standing at the ground fioor havingpreviously travelled in a downward direction, there being no outstandingunanswered calls for the lift carriage and the gates on all floors beingshut.

A group of relays, such as effective call relay GE, u-call storage relayGU and down-call storage relay GD on the ground floor, is provided foreach floor served by the lift carriage, the total number .of such relaysbeing 311. where n is the number of floors; in the presentrepresentation (n being four) there are 12 relays and connection tothese relays is made by wires I, 2, 3, and 4 which traverse the liftshaft.

It will be seen that the number of wires is equal to the number offloors served and this is a distinctly useful feature as compared withthose systems in which the necessary number of such wires varies as thesquare of the number of floors served.

The Wires I, 2, 3, and 4 are connected to groups of non-locking, callpush buttons GP. IP, 2P, and 3P situated on the ground floor, first,second and third floors respectively. Each group consists of threebuttons, such as, in the case of group GP, for example, GPI, GP2 andGP3, each of which is separately operable. If a person on the secondfloor wishes to travel in the lift to the ground floor he pushes callbutton 2PG of the group of buttons on the second floor. is on the firstfloor and wishes to travel to the top floor, he pushes call button IP3of the group of buttons of the first floor.

It may happen that the lift is in use when a person makes a call for thelift carriage to convey him to a particular floor, and it is tosafeguard this state of affairs that the groups of three relays, aseffective call relay GE, up-call storage relay GU and down-call storagerelay GD for the ground floor, are provided.

It is arranged that if the lift carriage is, say, at the first fioor,having previously travelled upwards, and a person presses a push buttoncorresponding to the second or third floor (i. e. if he presses callbutton IP3), then the effectivecall relays IE and 3E operate to causethe lift to.

move to the required floor immediately. Should the person on the firstfloor press the call button IPG, indicating that he wishes to be carriedto the ground floor then, since the lift carriage has been travellingupwards, the down-call storage relays ID and GD operate, the liftmeanwhile answering any up-calls that may have been made.

Similarly if the lift carriage has been travelling donwards and anup-call is made, say, at the second floor for the third floor, theup-call storage relays EU and 3U are operated.

Stored calls are answered when there are no more opposite-directioncalls to be answered.

The call button groups, such as GP, and the effective-call and storagerelays employ three separate batteries, the terminals of which areconnected to the points marked +U U, +E E, and +D D, (see lower leftFig. 3 and at respective relays Fig. 1b) these batteries being used forup-call storage, effective call, and down-call storage signalsrespectively.

The stored signals are converted automatically If he in this system toeffective call signals in their 75 correct order, the lift beingadapted, however, to.

answer all calls involving travel in a single direction, beforereversing and travelling to answer any calls which may be storednecessitating travel in the opposite direction, as will be shown later.

Slow acting up and down travel relays UR and DR for completingenergizing circuits of the updirection relay R and down-direction relayK respectively, are adapted to be actuated, through resistances YD, YErespectively, when the effective-call actuated relay EC is energized.The

energizing circuit of the efiective-call-actuated relay EC includes thecall-responsive relay C which controls the operation of another slowacting, transfer relay T which, in turn, controls the operation of stillother slow-acting up and down storage-circuit-holding relays CU and CD.The function of the storage-circuit-holding relays CU and CD is tocontrol holding circuits for the up-call storage relays GU, IU, 2U, 3Uand for the down-call storage relays GD, ID, 2D, 3D, respectively.

In order that the operation of the lift system may be fully understoodit is now proposed to outline the different sequences of actuation ofthe relays when the lift carriage answers some specimen calls.

It should be borne in mind. that the drawings show the positions of therelay contacts when, as has been mentioned above, the lift carriage isstanding at the ground floor with no stored calls and with the liftgates all shut, the lift having previously been travelling in a downwarddirection.

Assume that a call is made at floor 1 for the carriage to travel tofloor 3. The call is sent by momentarily depressing call push IP3. Thefollowing operating sequence now takes place:-

Up-call storage relay IU is operated over the path U, coil of relay IU,lead 2, centre contact of call button IP3, contacts 2 3, 3 3 and M to +Uthrough resistance YA.

Similarly up-call storage relay 3U is operated over the path -U, coil ofthe relay 3U, lead 4, lowest contact of call button IP3, contacts M3, M3and b4 to +U through resistance YA.

Contacts of up-call storage relay IU actuate as follows:

Iul locks the relay IU operated over lead 6 in series with up-callsignal relay US and call responsive relay C through contact cul; relaysUS and C operate.

Iu2 prepares a holding circuit for effective-call relay IE.

Iu3 opens a short circuit applied to up-travel relay UR from positive oncontact gfl through contacts ge3, gu3, gdS, Id3, Ie3, let, me, 2113,2e3, Zed, 2253, 321.3, 3(13, 3e3. Up-call signal relay US operatescontact usl and removes a positive potential from the opposite side ofup travel relay UR at the same time contact Iu3 opens the short circuitand so prevents operation at this time, but an operating positivepotential is shortly to be applied to the opposite side of up travelrelay UR by contact e02.

lu l prepares an energizing circuit for retardation relay G. Contacts ofup-call storage relay 3U actuate as follows:

3uI locks the relay 3U operated in series with up-call signal relay USand call responsive relay C.

3u2prepares a holding circuit for effective-call relay 3E.

Sui-further opens the path short-circuiting up- .travel relay UR asabove described.

The con-tact cl of'call responsive relay Cactuates to operate. celltransfer relay T.

Contacts of call transfer relay T actuates follows:

tl operates the effective call relay IE through contact bl, lead 8, andcontact Iu2 and operates effective call relay 3E through contact bl,lead 8 and contact m2.

112 operates up storage circuit-holding relay CU through contact b2.

t3 prevents operationv .of-direction setting relay B when. up-travelrelay UR is operated later.

Contact earl of up-storage circuit-holding relay CU cuts. the holdingcircuits of up-call storage relays IU and 3112.1; contacts. Iul and3101; these relays thereupon release as does upecall signal relay US.

By these operations, the .call registered through upcall storage relaysIU and 313 in the first place as a stored-up call, since the previousmovement of the lift carriage had been away from the call, istransferred into an effective call, i. e. one to which the lift carriagemay respond immediately. The sequence of operations causing response ofthe lift carriage to a now effective call from floor 1 for the lift totravel from that, floor to floor 3 is as follows:-

Effective call relays IE and 355.. have now been operated and theirrespective contacts actuate as follows:-

Ie l. completes, aholdingcircuit for the effective call relay IE throughlead 9 and effective. callactuated relay .EC and call. responsive relayC to the positive terminal of .:a battery.

Ie2 prepares. an operating circuitfor retardation relay G.

Ie3 and Ie4 break further. the path short-circuiting the up-travel relayUR.

3.eI duplicates the actuation of IeI, but the.

holding oire-uitlis for the effectivecall relay 3E.

3e2 prepares an operating circuit for retardation relay G.

3e3 breaks still further. the path short-circuiting the up-travel relayUR.

The effective-call-actuated relay EC is operated by closure of contactsIel and 3el.

ecl breaks a possible operating circuit for retardation relay G.

e02 operates up-travel relay UR by connecting one side thereof to thepositive terminal of the battery.

e03 actuates for possible operation of downtravel relay DR.

The up-travel relay UR. is operated and its contacts actuate as follows:

url opening prevents false operation of downtravel relay DR.-

ur2 tie-energizes call .transfer relay T, which being lagged, releases.slowly. I

m3 prepares an operating circuit fordirectioncutting relay B.

ur l energizes the .up-edirection relay R and the brake coil BS inseries over the path contact kl, coil of R, contacts-:st2 (operated) andml and brake coil BS to the negative terminal of the battery.

The brake is removed from the motor shaft at the sametime astheup-di-rection relay R is operated.

Contacts of the call transfer relay T (de-energized) actuate in thefollowing manner:-

tl breaks the call transferring circuit through contact bI.

t2 releases the up-storage-circuihholding relay CU.

t3 operates direction settingrelay B, through contact m3, to a positioncorresponding to an upward travel of the lift carriage.

Direction-setting relay B is of the two-position type for example asshown in British patent specification, No. 354,847, and its contactsactuate thus:

bi changes the call transferring circuit so as to be ready to deal withfuture registered downcalls.

b2 changes over from up-storagecircuithold ing relay CU todown-storage-circuit-holding relay CD.

123 changes from paths linked with contacts gwi, m4 and fu l to. pathslinked with contacts ld l, 2(14 and 31%.

b4 and b5 change over the battery connections to the call button groupsGP and 3P to effect appropriate call storage conditions, but no furtherrelays are operated even though the call button 5P3 is still depressed.

Actuation of the contactsof the up-direction relay R is:

rl prevents simultaneous operation of the down-direction relay K.

1'2 locks the up-direction relay R operated (it is released later, aswill be shown, by operation of braking relay NR).

T3 and r4 energize the lift motor M so as to drive the lift carriage LCupwards.

The lift carriage now travels upwards and, if desired, automaticaccelerating devices, not shown, may be employed, in order to produce asteady rate of increase of acceleration. Such devices are well-known andneed not be further discussed here.

Then mid-way between the ground floor and the first floor, the cam CJ lon the lift carriage LC operates contact J l to the left in the drawing,thereby releasing the follower relay GF and energizing the followerrelay IF.

If! transfers the point at which the short-circuiting path was appliedto the up-trav-el relay UR to another point in the contact chain Q63 to363. The short-circuit previously provided by positive at contact oil isremoved by release of the follower relay GF.

U2 and H3 actuate to. prepare the call button circuits for possibleactuation of contacts b5 and D4 to +E.

lf i de-energizes effective-call relay IE which releases.

I I5 operates retardation relay G through contact ieZ; the retardationrelay G locks operated through contact gi to contact m2, meanwhilecontact g2 operates haltrelay H.

lft and l fl serve no particular purpose in the operation immediatelyunder consideration. The contacts of the halt relay H actuate asfollows:

hl prepares to lock the halt relay H operated while a lift gate at anyfloor is opened, or until after the lapse of a predetermined time (aswill be describedlater).

hi prepares an operating circuit for the braking relay NR. The liftcarriage now approaches the first floor from which the call was made.When near the floor, the stop relay P is operated and its contact plcauses operation of the braking relay NR. The stop relay P remainsoperated as long as the lift carriage is near or standing at the floor.

nrl de-energizes the brake coil BS. This reapplies the brake to themotor driving shaft, causing slowing down and eventual stoppage at thefirst floor. At the same time this contact m'l de-energizes theup-direction relay'R causing de-energization of the motor M.

nr2 releases the retardation relay G.

The would-be passenger opens the lift gate at the first floor openinggate lock contact VI as he does so. This releases the starting relay ST.

stl holds the halt relay H operated while the gate is opened.

st2 opens the circuit of the up-direction relay R, the down-directionrelay K and the brake coil BS, so that no movement of the lift carriagecan take place whilst the gate is open.

Having entered the lift carriage LC, the passenger closes the gate oncemore; the starting relay ST is reoperated.

stl releases halt relay H.

st2 recloses the up-direction relay R circuit and the brake coil BScircuit.

The braking relay NR is once more released through breaking of contact712 so that the updirection relay R and the brake coil BS arere-energized in series to positive on contact m4; the up-travel relay URis still energized to negative battery through the resistance YD as,although the point of application of positive potential to the contactchain 3e3 to ge3 has been moved from of! to Ifl, effective-call relay 3Eis maintained operated and its contact 3e3, being open, prevents theup-travel relay UR from being short-circuited by this contact path.

The lift now travels in an upward direction releasing the stop relay Pand in turn operating the follower relays 2F and 3F through cams CJ 2and 0J3 cooperating with the contacts J2 and J3 respectively.

Operation of follower relay 2F effects no control of the lift as therelays are set for travel to the third floor only.

When the follower relay 3F operates its contacts actuate in thefollowing manner:-

3ft transfers the point at which the short-circuiting path was appliedto the up-travel relay UR to the end of the contact chain 3e3 to ge3,thereby short-circuiting the up-travel relay UR; the short-circuitpreviously provided by positive at contact I I is removed by release ofthe follower relay IF.

3f2 and W3 prepare the call button circuits for possible actuation ofcontacts b5 and 124 to +E through resistance YC.

3f4 de-energizes effective-call relay 3E which releases.

3 5 operates the retardation relay G through contact 362; theretardation relay G locks operated through contact gl to contact m2,contact I g2 meanwhile re-operating halt relay H.

. 3)!5 prepares another operating circuit for retardation relay G.

Halt relay H operates as before and its contact 11.2 prepares anoperating circuit for the braking relay NR which is operated as abovedescribed when the lift carriage approaches the floor where inductorplate F1 3 operates stop relay P.

The contacts of braking relay NR perform functions already described andthe lift carriage is brought to rest at the third floor as required.

Effective call relay 3E being released, as above stated, this clears thesystem of all unanswered calls and release of starting relay ST, haltrelay H and braking relay NR by the opening and closing of the lift gateon the third floor renders the system capable of dealing with furthercalls.

As already stated the lift carriage is adapted to answer all callsinvolving travel in a single direction before reversing and travellingto an-75 swer any calls which may be stored necessitating travel in theopposite direction. Thus when the lift carriage is at floor 3, a call ismade necessitating travel from floor 2 to the ground, floor, and whilstthe lift carriage is travelling towards floor 2 another call is madefrom floor 1 to floor 3, the lift carriage answers the two calls in theorder in which they are made. This is performed as follows:

The first call is made by depressing call button 2PG. Down-call storagerelays 2D and GD are thereupon operated. The circuits for these relays2D and GD are from +D resistance YB contacts 125, M2 (now closed), l 2call button ZPl to the relay coils and thence to D. When operated thetwo relays lock through contacts Edi and gdl respectively over lead 5 inseries with downcall signal relay DS and call responsive relay '0 bothof which operate.

The short-circuit applied to down-travel relay DR by a positivepotential at 3ft is removed by actuation of relay contacts ids and 9113,with the result that the down-travel relay DR is operated when contacte03 actuates later; the sequence of operations involving the operationof the effectiv'e-call-actuated relay EC need not be repeated here as itis similar to the sequence detailed above.

Previous to the operation of the down-travel relay DR the call,registered as down-call on down-call storage relays 2D and GE, ischanged to an effective-call and the registration is transferred to theeifective-call relays 2E and GE as follows:--

When call responsive relay C operates, its con+ tact cl operates calltransfer relay T.

tl applies positive potential through contact bl (now in a right handposition), lead 7 and con tacts M2 and get to efiective-call relays 2Eand GE Which thereupon operate.

t2 energizes down-storage-circuit-holding relay CD.

153 prevents direction setting relay B from changing over.

The contact cdl of down-storage-circuit-holding relay CD releases thedown-call storage relays 2D and GD, though only after contacts of theserelays have operated the effective-call relays 2E and GE as abovedescribed.

The call transferring operation is thus effected, the call now being aneffective call.

Operation of the effective-call relays 2E and GE causes actuationof theeffective-call-actuated relay EC in series through contacts Zel and gel.The effective-callactuated relay EC actuates as follows:

ecl breaks a possible operating circuit for the retardation relay G, I

ecZ actuates for possible operation of up-travel relay UR.

e03 operates the down-travel relay DR by connecting one side thereof tothe positive terminal of the battery.

Operation of the down-travel relay DR initiates downward travel of thelift carriage, this travel being performed in a similar manner to thatalready described in connection with upward travel,

'ex'c'ept ofcourse that the down-direction relayK is this timeoperated-through actuation of contact dr4-and, through its contacts k3and k4, starts up the motor M in the reverse directioncZr3 closes anoperating circuit for the direction setting relay B which is once moremoved to the position shown in the drawing.

'drZ opens the operating-circuit of call transfer relay T;

drl prevents false operation 'of the up-travel relay UR.

The contacts of the can transfer relay T actuate to perform thefollowing operations:--

it! opens the call transferring circuit through contact bl. i

t2 de-energize's the down-storage-circuit-holding relay CD thus enablingfurther down calls to be stored.

t3 completes the operating circuit for the direction setting relay Bthrough the contact d1'3.

The lift now travels'to floor 2 and stops in a manner "similarto thatalready described, entry of the passenger and reclosing of the liftgates causing the lift carriage to restart in a downwarddirectiontowards the ground floor.

A call is made from floor 1 to'floor 3 by the depression of call buttonlP3; a circuit is thereupon completed from +U through resistance YA,contacts 5713 (closed)-and U3, call button IP3, leads 2 and 4 and coilsof the up-call storage rela'ys3U and 'lU to -U, and these two relaysoperate. As the call transfer relay T is at present de-energ ized bycontact dr2, the contacts luZ and 3a? cannot operate'the effective-callrelays IE and 3E, i.--e-.-the second call cannot be transferred into aneffective one, until the down-travel relay DR is released once more whenthe lift carriage reaches thfground floor, where it is brought to restby actuation of the retardation relay G through contacts yrs and edZ.

As the liftcarriage cam CJl actuates contact Jl midway between the firstand the ground floors, the followerrelay GE is operated andfollowerrelay lF-is released, this transferring a positive potentialfrom III to of l and short-circuiting down trav'el relay DR whichreleases slowly.

drlcloses, there being no need to safeguard false operation of up-travelrelay UR.

drZ energizes call transferrelay T (call-responsive relay'C beingoperated in series with up-call signal relay US due to the registeredup-call from floor 1 t'o'floor 3).

r173 further opens the operating circuit for direction setting relay B.

dM slowly opens the circuit of the down-direction relay K;

tl operates 'eifective-call relays IE and 3E through contacts bl (inposition shown) and H62 and 3u2 respectively.

t2 energizes the up-storage-circuit-holding relay. CU which cancels thestored upcall by releasing up-call storage relays lU and 3U at itscontact cul.

The operation of the lift carriage is not yet affected by thistransference as the down-direction relay K is locked operated throughcontact ml, which will Ice-opened only when the carriage reaches theground floor. When the down-travelling passenger reaches the groundfloor and has opened the lift gates and the retardation relay G, haltrelay H and braking relay NR have been released, closure of the liftgates enables uptravel relay UR, which is operatedby the opening ofcontacts 163 and 3e3, to'operate the up-direction relay R and'the liftcarriage travels to the first floor. Here the carriage stops in themanner already described, picks up the waiting caller, restarts upwardsand travels to the third floor.

Now a thir'cl'example of the operation of the lift system isthat inwhich calls are made simultaneously from,- for exam iegtn'e ground floorto the second floor and from the first floor to the third floor. Thelift will be considered as being again at the ground floor so that therelays-and contactors are in the positions shown in the drawing.

In this example, the call-buttons GP2 and IP3 are depressed GPZ beingassumed to be depressed a few seconds prior to IP3.

Up-call storage relays GU and 2U are initially operated over the path+U, resistance YA, contacts M, U3, U3, and If3, call button GP2, therelay coils and U. This call is transferred into an effective callimmediately since the operation of call responsive relay C in serieswith the upcall signal relay US, as will be clear from the precedingdescription, completes at its contacts cI the operation circuit for thecall transfer relay T, so that the lift carriage commences to travelupwards. Meanwhile the call button IP3 has been depressed (actually forthe following sequence of operations to take effect, it must bedepressed before the lift carriage cam CJI has operated contact J I) andeffective-call relays IE and 3E are operated over the path +E,resistance YC, contacts 224 (now operated to right hand position), 3 3,2f3, call button IP3 to E through the operating coils of the relays.Then,'although the lift carriage was originally going to travel to thesecond floor before stopping, it now stops at the first floor on the wayas its movement is arrested by the operation of the retardation relay Gfrom contacts I I5 and Ie2. When the second passenger has entered thecarriage and has closed the gates, the carriage re-starts upwards, stopsat floor 2, re-starts a second time and finally comes to rest at thethird floor, whence it travels to answer any other calls thatmay havebeen made. The detailed operation of the system to bring about therestarting and subsequent movement of the lift carriage will be clearfrom the previous description of similar operations and will not beexplained here.

Now it may happen that the lift carriage is standing at the ground floorand call is made for the carriage to convey a passenger from the secondfloor to the first. It is obvious that the call is un-convertible intoan effective call immediately as to answer the call, the carriage musttravel to the second floor and then reverse its direction of travel. ItWill be as well therefore to point out the sequence of operationsperformed by the. system in answering such a call. These are as follows:

When the call is made, the depression of the appropriate call button 2PIcauses operation of the down-call storage relays 2D and ID over the path+D, resistance YB, contacts 3 2, 2f2, call button ZPI to D through thecoils of the downcall storage relays 2D and ID. Down-call signal relayDS and call responsive relay C are operated at the same time as thedown-=call storage relays 2D and ID.

cI operates the call transfer relay T, but, as the contacts ofdirection-cutting relay B are actuated to the positions corresponding tothe transference of stored up-calls only, no transference takes place.

As however down-call storage relay 2D is operated, its contact 2d3removes the short circuit from the up-travel relay UR which operates topositive at contact dsI (operated) through contact drI to negativethrough resistance YD. Operation of the up-travel relay UR initiatesupward travel of the lift carriage in the manner already clearlyoutlined until the lift carriage cam 0J2 moves contact J2 over andconsequently actuates the follower relay 2F. A circuit is thereuponcompleted from positive at contact Zjl, through contacts 2114, 30 .4, b3and cal to negative through the coil of retardation relay G which istherefore actuated and then looks through its contact gl. When the calltransfer relay T was released on the operation of up-travel relay UR thedirection setting relay B and consequently the contact 113 was operatedto a position to effect transfer of stored down-calls.

Then the lift carriage stops at the second floor and the passengerenters and closes the lift gates, the stored down-call is transferredfrom downcall storage relays 2D and ID to effective-call relays 2E andIE, the call thereby becoming effective. Travel of the lift carriage ina downward direction then follows, the carriage stopping at floor 1 toenable the. passenger to alight. Closure of the gates once more rendersthe system ready to answer calls in or for either direction.

Further facilities afforded by the lift system according to theinvention are of known type. For example, should the lift carriage byany means over-run its normal extent of travel, the limit contact TL orBL is operated at the top or bottom of the shaft thereby releasingstarting relay ST, the contact SW of which de-energizes whichever up ordown direction relay R or K is energized and applies the brake byde-energization of the brake coil BS. In addition a delay device (notshown) connected to lead I0 (Figure 3) can be provided in order toensure that the lift carriage stops sufficiently long at the floor inorder to enable the passenger to enter or leave the lift carriagewithout its being started away from the floor before the gate can beopened. This delay circuit can be of any known type such as thatafforded by a thermostat or dashpot the action of which is initiatedeach time the lift carriage stops at a floor. The action of thethermostat or other delay consists of applying a holding potential tolead If! for a period of, for example, 5 seconds, this preventing therelease of halt relay H and consequently holding braking relay BR.operated, contact m'I of which prevents operation of either of the up ordown direction relays R or K. This facility may be combined withanother, that of causing the lift to drive to a predetermined parkingposition if the lift remains unused after a further predeterminedtime-say one minute. A circuit whereby this may be effected is shown inapplication Serial No. 12,332, in which a neon tube relaxation dischargecircuit is shown as stepping a switch which provides various timedelays, although the invention does not necessarily involve the use ofthis particular circuit. The circuit shown in the aforementionedapplication also provides means whereby the power supply to the. liftdriving motor may be removed at the end of a still further time delay,this being useful when the lift motor is driven from a Ward-Leonardmotor generator set, in which case, when the lift is out of use, it iseconomical to shut down not only the lift driving motor, but also themotor generator. If the lift carriage has been moved to a parkingposition, or if the motor generator set has been shut down, and a callappears, the delay circuit is reset, the motor generator re-started, andthe whole cycle is ready to be recommenced after the call has beenanswered.

I claim:

1. A push button operated automatic lift controlling system comprising agroup of floor call buttons at each floor, a group of three relays'foreach floor including up and down call-storage relays and aneffective-call relay, independent circuits for operating said relays byoperating floor call buttons, a transfer relay for transferring callsfrom call-storage relays to effectivecall relays, a relay arranged to beoperated by' call-storage relays for effecting operation of saidtransfer relay and relay circuits controlled by the effective-call relayfor operating the lift in response to the floor button depressed.

2. A push button operated automatic lift controlling system as in claim1 wherein relays controlled by said elfective-call relays and therespective up and down call-storage relays are provided for determiningthe direction of motion of the lift and for stopping it at the requiredfloors.

3. A push button operated automatic lift controlling system comprising agroup of relays for each floor including up and down call-storage relaysand an effective-call relay, circuits for operating said relays, a groupof floor call buttons at each floor for closing the respective circuitsfor operating said relays according to the calling floor and thedestination, relays arranged to operate in series with the respectivecall-storage relays for determining the direction of travel of the lift,a transfer relay for effecting operation of the correspondingeffective-call relays for transferring calls thereto from the operatedcall-storage relays, a relay operated in circuit with the effective-callrelays for controlling circuits for effecting operation of the lift in adirection responsive to call buttons operated,

4. A push button operated automatic lift controlling system as in claim3 wherein relays including a double-throw relay arranged to becontrolled by said effective-call relays and the transfer relay areprovided for determining the direction of motion of the lift.

5. A push button operated automatic lift controlling system as in claim3, wherein follower relays arranged to be actuated by the lift inpassing from floor to floor are provided for controlling the circuits ofsaid call-storage relays and for effecting operation of other relays forstopping the lift according to floor call buttons operated.

6. A push button operated automatic lift controlling system comprising agroup of floor call buttons at each floor, means including an upcallstorage relay for each floor, means including a down call-storagerelay for each floor, independent circuits for said up call and downcall relays respectively, the respective call buttons at each floorbeing arranged for operating at least two of said call-storage relays,one for the calling floor and one for the floor called, a transfer relaycontrolled by said call-storage relays, means including an effectivecall relay for each floor arranged to be operated by said transferrelay, for effecting operation of the lift in the direction required bythe call, follower relays arranged to be operated by the lift as itpasses from floor to floor and relays and circuits controlled by saidfollower relays in cooperation with said effective-call relays fordetermining the direction and extent of travel of the lift.

7. A push button operated automatic lift controlling system comprisingan up call-storage relay, a down call-storage relay and an effectivecallrelay for each floor, a group of floor call buttons at each floor forcalling each of the other floors, independent current sources foroperating the respective relays, two circuits from each of saidcall-buttons for simultaneously operating two corresponding relays, onefor the calling floor and one for the floor called, directiondetermining relays arranged to be operated by the up and downcall-storage relays, a transfer relay arranged to be operated by thecall-storage relays for transferring calls by operating the twoeffective-call relays corresponding to the two callstorage relays,operated by the call button, and relays and circuits controlled by theeffective-call relays for stopping the car at the calling and calledfloors.

8. A push button operated automatic lift controlling system as in claim7, wherein a relay arranged to be operated in series withoperatedeffective-call relays cooperates with follower relays operatedby the lift in passing from floor to floor for controlling the stoppingof the car successively at the calling and called floors as indicated bythe operated call-storage relays.

9. A push button operated automatic lift controlling system as in claim'7 wherein a starting relay operated by up and down limit switches andby the opening and closing of gates at the respective floors is arrangedto control operation of the lift motor and follower relays operated bythe lift in passing from floor to floor cooperate with operatedeffective-call relays for stopping the lift at the calling floor andopening and closing of the gate at that floor by operating said startingrelay permits immediate restarting of the lift toward the called floorwhen the gate is closed.

10. A push button operated automatic lift controlling system comprisingcall-storage relays for up and down calls and an effective-call relayfor each floor, a group of floor call buttons at each floor, each callbutton being arranged to close circuit for operating at least twocorresponding relays, one for the calling floor and one for the floorcalled, independent current sources for operating the respectivecall-storage and effectivecall relays, a plurality of contactors fordetermining which of said current sources is utilized when a call buttonis operated and relays arranged to be operated according to thedirection of movement and position of the lift and which call-storageand effective-call relays are operated for positioning said contactor,the arrangement being such that if call buttons are operated on twodifferent floors which may be served in succession, the effective-callrelays are operated directly by the push buttons from one of saidindependent current sources.

NORMAN CAROL SMART.

